According to The Washington Post, the United States has been concerned over the possibility of Iranian forces, fighting in support of the Syrian government, seizing the US outpost in al-Tanf. Other high-ranking aides were cited by the media outlet as saying that they saw it as a chance to expand the campaign against the Iranian forces in the war-ravaged country.
Such a turn of events would contradict President Donald Trump’s promise to “leave Syria, like, very soon” as the US has allegedly accomplished its mission to “knock out” Daesh*.al-Tanf base’s fate illustrates the confusion characterizing President Trump’s response to Iranian increasing "political and military influence" across the region. Initially, the base was established to fight armed militant groups and recapture a strategic border crossing at Bukamal, but since Trump took office, he promised to act decisively against the Islamic Republic, which allegedly joined Syrian government troops and frustrated US plans to move northwest.
As President Trump accused Tehran of fomenting “violence” and fueling “bloodshed and chaos” across the Middle East, the anti-Daesh mission in al-Tanf smoothly shifted to countering the alleged Iranian presence in the area. Trump’s top military aides are, however, reluctant to kick-off a larger campaign in Syria out of concerns over the safety of troops positioned in the region.
Tensions between the US and Iran have recently escalated as President Trump announced his decision to withdraw from the Iran nuclear deal and reinstate anti-Tehran sanctions. The situation is being exacerbated by Israeli strikes on alleged Iranian positions in Syria in response to Tehran purportedly firing rockets at the IDF forces positioned in the Golan Heights. Iran, in turn, denied its military presence in Syria.
Since 2016, the US has been training Free Syrian Army militants at its military base in al-Tanf to fight Daesh, however it has drawn much criticism from Damascus and Moscow, with the latter voicing concerns that Washington was “spewing Daesh mobile groups who make inroads to launch subversive terrorist operations against Syrian troops and civilians.”
"The situation when the United States is virtually occupying a 55-kilometer [34-mile] zone around At-Tanf on the Syrian-Jordanian border without the consent of the Syrian Government, is bewildering. This zone includes the infamous Rukban refugee camp, where militants from illegal armed groups are freely moving near the US Armed Forces," the assistant to the secretary of the Russian Security Council told Sputnik.
The US-led coalition has been conducting airstrikes against Daesh targets in Syria since 2014 without a UN mandate or authorization from the Damascus government. Syria views their presence as a violation of the country's national sovereignty.
*Daesh, also known as ISIS/ISIL/IS, is a terrorist group banned in Russia and many other countries.